Conventionally, this kind of filmy coil has been manufactured using a material which carries a conductive layer such as a metallic foil, a deposit, or a metallic deposit. On the surface of said conductive layer a patterned resist layer is provided, and then the surface, namely, one side of the conductive layer is etched chemically to form a linear conductive layer. With this conventional manufacturing method, however, there is the disadvantage that it takes a lot of time to etch the conductive layer from one side until it is penetrated, which raises the production cost. Moreover, particularly from a technical viewpoint, as the quantity of side etching is increased excessively and the width of a line is thinned (see FIG. 1), the interval between the lines is enlarged in order to attain a conductive layer of a proper-width-line (see FIG. 2). Therefore, another disadvantage is that a low-patterned coil is the best that can be produced.